1. Field of the Invention
The subject invention is directed generally to adapters for electrical stimulation leads, and more particularly, to adapters for connecting cardiac leads to electrical therapeutic and/or diagnostic devices such as cardiac pacemakers and/or defibrillators.
2. Background of the Related Art
Electrical stimulation devices for cardiac and neurological stimulation are well known in the medical field. Cardiac stimulation devices are used for therapeutic and/or diagnostic purposes. These devices, which include cardiac pacemakers and implantable cardiac defibrillators, generally interface with cardiac tissue by means of implantable or otherwise attachable cardiac leads. These leads employ connector portions to operatively connect with matching receptacles located in the therapeutic and/or diagnostic devices.
In operation, electrical therapeutic and/or diagnostic devices for the heart send and/or receive electrical signals from heart tissue. These signals are carried to and from the devices through conductors which form part of the cardiac leads. In order to properly conduct the signals, the cardiac leads must make proper electrical contact with the electrical therapeutic and/or diagnostic devices.
Connectors typically include one or more electrical contact points or poles, to communicate signals between the electrical therapeutic and/or diagnostic device and the leads to which it is connected. These poles are either anodic or cathodic. Anodic poles are generally relatively positive in polarity and cathodic poles are generally relatively negative in polarity.
Connectors are available in various configurations which are often of standardized types readily recognized by those practicing in the art. Connector types may differ from one another in connector diameter, connector length, connector shape, placement of electrical contact points and other geometric or functional properties. It is well understood by those practicing in the art that connectors of one type cannot directly connect to receptacles designed to operatively accept a different type of connector. Receptacle type is thus determined by the connector type which the receptacle may operatively accept.
Common connector types well known in the art currently include: IS-1 type (International Standard ISO 5841.3:1992) pacing/sensing connectors which have a 3.2 mm diameter and are available in unipolar or bipolar configurations; LV-1 type pacing/sensing connectors which have a 1.8 mm diameter and are available in unipolar and bipolar configurations (Guidant Corporation); and DF-1 type (International Standard ISO 11318:1993) defibrillator connectors which have a unipolar configuration.
Some leads, such as those used in conjunction with implantable cardiac defibrillator (ICD leads), employ multiple connectors. For example, leads are known which employ one or two DF-1 type connectors and one or two IS-1 type connectors, all of which are combined at a yoke portion of the lead.
It is envisioned that other standardized and non-standardized connector types may be developed and utilized in the future as new materials and fabrication techniques are introduced and as specific needs of practitioners change. For example, IS-4 type connectors are being introduced which combine two unipolar DF-1 type connectors and one bipolar IS-1 type connector in a single connector. IS-3 type connectors have also been considered, but have not become standardized.
It is often desirable to utilize more than one lead in conjunction with a single receptacle of an electrical therapeutic and/or diagnostic device. In order to do so, practitioners in the relevant art utilize connection adapters, which generally consist of a connector portion and a receptacle portion. These devices are generally designed to work with only a single connector type; that is, the receptacle portions of these devices are adapted to operatively accept only one type of connector. Utilizing the devices currently known in the art, practitioners are unable to utilize multiple leads having different connector types with a single receptacle of an electrical therapeutic and/or diagnostic device. It would be beneficial therefore, to provide an adapter configured in such a manner so as to enable practitioners to utilize stimulation leads with different types of connectors concurrently with a single receptacle of an electrical therapeutic and/or diagnostic device.
When utilizing two or more cardiac leads with an adapter, it is often desirable to delay the transmission of electrical signals to one or more of the leads connected to the adapter. For example, adapters of the present invention are used in some instances for bi-ventricular pacing or re-synchronization of the right and left ventricles in the treatment of congestive heart failure. In these applications, practitioners sometimes desire to introduce a predetermined delay in the delivery of the pacing energy (i.e., the electrical signal) from the electrical therapeutic device to the heart tissue via one or more cardiac leads.
It would therefore be beneficial to provide an adapter having circuitry for programmatically delaying the transmission of electrical signals from the electrical therapeutic and/or diagnostic device to one or more of the cardiac leads connected to the adapter, thereby permitting practitioners to control the sequence and timing of the transmission of signals to one or more cardiac leads.